1) Field of the Invention
The present invention relates to an improved artificial insemination device with an inner catheter for animals, more particularly, a simple, practical, ideal and inventive device that is easy and convenient to use and allows animal semen to reach the two ducts to uterine horns or the uterus swiftly and smoothly, thereby improving the success rate of artificial insemination and effectively saving the amount of semen needed. The invention herein requires minimal amounts of insemination semen and offers economic benefit. It also renders artificial insemination safer, more hygienic, and more humane.
2) Description of the Prior Art
The assembly and operation of conventional artificial insemination device for animals as shown in FIG. 1 and FIG. 2, typically comprises a plastic catheter tube 10 of certain hardness and a nozzle 20 made of softer material installed protrusively on the front end of catheter tube 10. When artificial insemination is carried out, the catheter tube 10 and nozzle 20 are inserted along the vagina 11 of female animal body 1 until the nozzle 20 at the front penetrates into cervical tract 12. Subsequently, the insertion tube 31 of the semen dispenser (bag or syringe) 30 containing the animal semen is inserted into the rear end of catheter tube 10, and as the operator continuously squeezes the semen dispenser (bag or syringe) 30, the semen contained therein is ejected into the cervical tract 12 through the nozzle 20 of catheter tube 10, where the uterus 13 contracts to draw in semen from cervical tract 12. Although the configuration and operation of such artificial insemination device achieve the purpose of artificial insemination in animals effectively, there are some drawbacks:
1. After the catheter tube 10 penetrates the vagina 11 of female animal body 1, the nozzle 20 at the front is pushed approximately to the position of first cervical ring 121 of cervical tract 12, but there remains considerable distance between the first cervical ring 121 and the uterus. Although the contraction of uterus 13 could draw in the semen from cervical tract 12, a large amount of semen ejected from the nozzle 20 initially accumulates at the position of first cervical ring 121 and cannot instantly flow into the uterus 13. What happens most frequently is that the semen accumulated at the first cervical ring 121 often backflows outside the vaginal orifice 111. As such, not only semen is wasted, the amount of semen that flows into the uterus 13 is proportionately lessened, hence decreasing the probability of successful insemination.
2. In response to the problem of semen backflow, operators commonly dilute the semen fluid many folds (typically 5 cc is diluted into 50-120 cc) and enlarge the inner diameter of catheter tube to accommodate and provide more semen fluid for insemination. But the massive dilution of semen fluid apparently reduces the rate of fertilization and the number of fetus, while using more semen incurs waste directly.
3. As described above, the semen in catheter tube 10 is directly released from the nozzle 20, and when nozzle 20 penetrates the cervical tract 12 from outside the female animal body 1, the accidental admittance of contaminants from outside the body or the vagina 11 is difficult to avoid as the semen flows into the uterus 13. As such, the risk of bacteria infection and inflammation of the vagina, cervical tract, and even the uterus of the animal during artificial insemination is high and, at the same time, the safety of fetus carried in the uterus 13 is jeopardized.
4. To improve the success rate and safety of artificial insemination, the operation of artificial insemination requires professional personnel (such as veterinarians or specialized technical personnel) and, as such, to big animal farms (such as pig farmers), it incurs heavy economic burden and demands considerable professional manpower.
5. After the operator utilizes the catheter tube 10 and nozzle 20 to penetrate the vagina 11 and cervical tract 12 of female animal body 1, he has to use one hand to hold the rear end of catheter tube 10 and the other hand to grip and squeeze the semen dispenser 30, which is apparently more troublesome, inconvenient, cumbersome, and time consuming in operation.
To render animal artificial insemination process more efficient and humane, some operators would use accessory devices. As shown in FIG. 3, such devices include an AI Buddy 40, an elastic saddle-like apparatus resembling the two front legs of an animal, wherein a connector 50 with open posterior is installed at the rear end of catheter tube 10, with a positioning strap 41 disposed between the AI Buddy 40 and the connector 50; as such, during the artificial insemination procedure, the operator straddles the AI Buddy 40 over the back of the female animal 1 such that the female animal feels that a male animal has mounted with its two front legs, a guide bush 60 is then placed at the vaginal orifice 111 of female animal body 1 and after the catheter tube 10 and nozzle 20 penetrate the vagina 11 and reaches the cervical tract 12 through the guide bush 60, the rear end of catheter tube 10 is flexed upward and directly secured by the positioning strap 41 connected to the AI Buddy 40; following the ingress of a semen dispenser 30 insertion tube 31 into the connector 50, the operator only has to squeeze the semen dispenser 30. In such approaches, the operator needs to use both hands at the same time, one for grasping the catheter tube 10 and one for squeezing the semen dispenser 30, a procedure that is troublesome and time consuming, but nevertheless an effective improvement. However, existent shortcomings that have not been improved include semen backflow that wastes semen, which is uneconomical and lowers insemination success rate; the easy inflow of contaminants from the outside of the female animal body into the vagina, cervical tract, and uterus that endanger the health of the female animal and fetus carried in the uterus; and the requiring of specialized personnel for operation, which is uneconomical and involves additional manpower.
To increase the success rate of artificial insemination, an improved artificial insemination device for animals as shown in FIG. 4 and FIG. 5 (U.S. Pat. No. 6,526,917) has been disclosed, wherein the front end opening 421 of catheter tube 420 is inserted into a sheath-like membrane 410 and the leading edge 412 of membrane 410 is snapped into a positioning ring 422 of catheter tube 420. Subsequently, nozzle 440 is inserted into the front end of catheter tube 420 to immobilize membrane 410. After nozzle 440 is inserted into the front end of catheter tube 420, the various components including the member 410 sandwiched between nozzle 440 and catheter tube 420 can be further secured to each other by sonically welded or heat staked. The object of such artificial insemination assembly is to cause the tip 411 of sheath-like membrane 410 to begin unfolding in an inside-out manner not unlike removing one's sock by pulling from the open end when semen is squeezed into the rear end of catheter tube 420 and enters the uterus along the cervical tract where semen is ejected from the opening of tip 411 to enhance the efficiency of insemination, prevent the entry of contaminants into uterus, and prevent the backflow of semen. Such artificial insemination apparatus is more effective in comparison with prior art. But it still has some drawbacks in actual implementation:
1. Given that membrane 410 is inserted from the front end opening 421 of catheter tube 420 and secured to nozzle 440 via a leading edge 412, the tip 411 of membrane, when squeezed inside-out under the pressure of semen, must travel through the pathway B (FIG. 4) of nozzle 440 before entering the cervical tract of animal. Thus in order for membrane 410 to enter the uterus of animal, it must have certain length. As we know, the longer the membrane, greater squeeze force to expose it outside the nozzle is required, rendering the whole operation more troublesome. In particular when the semen dispenser is in bag shape, the force generated from squeeze is not as much as that of bottle or syringe, which construes a limitation in implementation.
2. Given that the leading edge 412 of membrane 410 is snapped into the positioning ring 422 of catheter tube 420, membrane 410 is tightly attached to the periphery of tube 420 under certain tension, and subsequently nozzle 440 is tightly conjoined to the periphery of membrane 410. What happens most frequently is that when the membrane 410 under tension is pushed by the exertion of nozzle 440, perforation tends to occur around the edge of front end of catheter tube 420 (shown as C in FIG. 4). In such event, when semen is squeezed into catheter tube 420, the perforation would cause air leakage, which keeps membrane 410 from being squeezed out quickly and smoothly, thereby resulting in poor execution or even the failure of artificial insemination.
3. Given that membrane 410 is inserted into catheter tube 420 from its opening 421, the inner diameter of catheter tube 420 (i.e. the hollow space 424) must be bigger. But bigger tube directly increases the consumption of semen, the same as in prior art. Such apparatus apparently does not offer the economic benefit of saving the usage of semen.
4. To prevent trauma to the animal during artificial insemination, the nozzle is usually made of elastomeric material. If the force used is improper or the animal does not stay still during artificial insemination, the front part of nozzle is prone to deformation or bend which might block the semen pathway. Under the circumstances, it is likely that the membrane 410 disposed inside catheter tube 420 will not extend under pressure to achieve artificial insemination.
5. As described above, membrane 410 must have certain length and is directly inserted in larger diameter in catheter tube 420. When the force from the squeeze of semen pushes membrane 410 out of nozzle 440 and into the cervical tract of animal, the long and large-sized membrane will encounter greater resistance inside the narrow and winding cervical tract and become more difficult to extend. More so, if the squeeze force is smaller, it is likely that the tip of membrane 411 will not reach uterus, rendering artificial insemination an unstable and uncertain operation.
FIG. 6 and FIG. 7 depict another artificial insemination apparatus for animals, characterized in which a longer plastic inner catheter 70 is movably inserted in the catheter tube 10 of a conventional device that comes with a nozzle 20, and a smaller second nozzle 80 is disposed at the forward portion of inner catheter 70. The object of such artificial insemination assembly is to allow the operator to advance the smaller inner catheter 70 inside the catheter tube 10 more smoothly along the cervical tract and bring the smaller second nozzle 80 to the location of uterus after the catheter tube 10 and nozzle 20 enter the cervical tract of female animal body and the nozzle 20 reaches the first cervical ring. Subsequently, semen contained in the semen dispenser (bag or syringe) is expelled from the rear end of inner catheter and enters uterus smoothly via the second nozzle 80. Undeniably, such design facilitates the delivery of semen to the uterus and the use of smaller inner catheter 70 saves the volume of semen required. Still operators find some deficiencies with the device after using it in actual operations. That is, when the inner catheter is extended inward, operator is unable to see if the second nozzle 80 at the front has reached the uterus and can only rely on experience to control the depth of inward extension. What happens most frequently in actual implementation is that the inner catheter 70 overextends and injures the uterus. In the attempt to prevent injury to uterus, some operators shortened the extension depth of inner catheter 70, which however defeats the original purpose of disposing such a tube and results in backflow of semen. Also, as the animal does not stay still during artificial insemination, a free-moving inner catheter 70 is prone to displacement during the procedure and causes trauma to the uterus.